Which world leader is on record musing about "a world without
America" - a goal he calls "attainable"? Iranian President Mahmoud
Ahmadinejad.

Until recently, it was possible to believe that whatever Mr.
Ahmadinejad's intentions, Iran was a long way from acquiring the
capabilities it needs to achieve its goals. But a blue-ribbon
commission has reported to Congress on what appears to be an
Iranian drive to obtain the means to carry out an EMP
(electro-magnetic pulse) attack.

An EMP attack is produced by launching a ballistic missile with
a nuclear weapon attached -- and detonating it high above the
Earth. This produces a massive pulse of ionized particles that
could damage or even wipe out many electrical and information
systems. Such an attack would disrupt telecommunications, banking
and finance, fuel and energy, food and water supplies, emergency
and government services and much more, threatening millions of
lives.

We've seen a blacked-out South Texas in the wake of Hurricane
Ike. We've seen New Orleans after Katrina. Now imagine that
scenario over most of the continental United States. There would be
a "world without America" - at least as we know it.

No one disputes that Iran is developing a robust long-range
missile force. Few question that Mr. Ahmadinejad's regime is
working on nuclear weapons development. Less well-known is that
Iran has conducted missile tests from sea-based platforms,
detonating warheads at the high-point of the missile trajectory,
rather at the aim point over the target. These facts have now been
documented in official government reports.

Connect the dots, and you find the picture of a workable
research program for developing a covert means to deliver an EMP
attack against the United States.

A short-range ballistic missile could be carried on one of the
thousands of commercial freighters sailing under "flags of
convenience" that sail around U.S. waters every day. Without ever
piquing the interest of the Navy, the Coast Guard, or the Customs
and Border Protection, that ship could sail within range and
deliver its payload over American territory. Even a modest warhead
placed at the right spot over the East Coast could take down 75
percent of the electrical grid.

The genius of such a covert attack is that it doesn't come with
an obvious "return address." The ship might be registered in
Liberia. The crew might be Lebanese. The ship might disappear into
the night - or be scuttled quietly.

Another advantage for a would-be attacker is the bang that can
be achieved for the buck. An EMP attack would allow an enemy to
wreak an enormous amount of destruction for a modest investment. It
would mean no electricity, no food on the shelves, no phone, no
fuel deliveries. Life would look more like the barter system of the
19th century, not to mention the millions that would die from
traffic accidents, fires, failed hospital equipment, disease and
the other chaos that would result from such an attack.

A lot can be done to deal with this terrible threat. For
starters, we need to build comprehensive missile defenses that can
shoot missiles down fired anywhere shortly after they lift off. We
also need to develop national plans to mitigate vulnerabilities to
an EMP attack and recover quickly from a strike if one does
occur.

America, however, also needs to dust off its nuclear deterrent.
Of all the nations that could pull off an EMP attack or hand that
capacity to a transnational terrorist group, Iran is the only
country that has directly threatened to destroy the United States.
While much America's infrastructure is vulnerable to EMP, the
nuclear strike force is not. We need to inform Iran that if an EMP
attack were unleashed on America, Iran could well be held
responsible and suffer massive nuclear retaliation.

Perhaps deterrence won't work. Middle East scholar Bernard Lewis
argues that to a devout believer in Ayatollah Ruhollah Khomeini's
apocalyptic ideology, mutually assured destruction may be "more an
inducement than a deterrent." Still, it's worth making it clear
that a steep price will be paid for such an attack.

In the end, President Reagan was right: Massive retaliation is
not a morally supportable option when there are real alternatives.
Comprehensive missile defenses, vigorous counterproliferation
programs, and making U.S. infrastructure more resilient are really
the best ways to protect and defend the nation. The next president
needs to make these a priority.

Indeed, demonstrating that America takes the threat seriously is
perhaps the best message we could send to Mr. Ahmadinejad and those
he represents.

Clifford D. May, is president of the Foundation for
the Defense of Democracies.James Jay
Carafano, a senior research fellow for national
security at The Heritage Foundation, is the author of the books
"G.I. Ingenuity" and "Private Sector, Public Wars."